Marine reptile reproduction

["Dino Rampage" <dino_rampage@hotmail.com>]

How did marine reptiles reproduce? I know that ichthyosaurs, mosasaurs & 
plesiosaurs were ovoviviparous, but what about the others? Is there any 
evidence for live-bearing in placodonts, "nothosaurs" & pachypleurosaurs? Or 
what about the modes of reproduction in basal ichthyosaurs & other more 
'primitive' marine & aquatic reptiles (eg. the sphenodont Pleurosaurus, 
aigialosaurs)

The marine turtles of the Mesozoic were most definitely egg-layers, but what 
about the crocodilians? I suppose that most like Thoracosaurus, Hyposaurus, 
Teleosaurus, Steneosaurus, pholidosaurs & dyrosaurs laid their eggs on land, 
but what about the marine forms like Metriorhynchus & Geosaurus, which seem 
to have been almost exclusively pelagic? Is there in any way the archosaur 
reproductive system could have become modified to allow live-bearing in 
these marine crocodilians?

And is there any evidence for marine 'snakes' in the Cretaceous?




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